1. Field of the Invention
The present invention relates generally to the field of multi-channel pumps. More particularly, the present invention relates to multi-channel pumps, wherein one or more fluids, including liquids, gases, and reagents can be selectively dispensed. Further, the present invention relates to addressable multi-channel peristaltic pumps.
2. Description of Related Art
Peristaltic pumps are used in a variety of applications, including in automated multi-channel reagent dispensing systems, for example, nucleic acid purification systems. Indeed, peristaltic pumps are useful for any multiple fluid transfer application, especially fluid transfer applications that would benefit from isolation of fluid from the system and other fluids.
Typically, peristaltic pumps comprise a mechanism for transporting fluid within flexible tubing by applying pressure to the tubing at select intervals. As positive pressure is applied to the tubing, fluid in the tubing is moved or “pushed” forward. As the positive pressure point is moved forward on the tubing, a negative pressure is created behind the point of pressure, thus, causing fluid behind the pressure point to be drawn into and “pulled” forward through the tubing. The mechanism for causing the fluid to move within the tubing can be, for example, of linear or rotary type. Very generally, means for compressing the tubing is used to force fluid through the system, such as by way of rollers or any solid support that could be used to apply pressure to the tubing. Using rollers, for example, pressure is applied to the tubing by the rollers to cause the walls of the tubing to compress, otherwise referred to as occlusion. When compressed, the tubing pushes fluid forward through the system, i.e., the fluid is pumped or dispensed. As the pressure point is moved to cause additional flow to the fluid (the pressure point in this example being caused by the roller), the tubing not under compression by the roller re-establishes its natural state. As the resilient tubing returns to its natural state, fluid is imported into the system and then exported through the system as pressure is re-instated.
In a rotary-type system, the tubing is situated between rotor wheels, which comprise one or more rollers, and a support, which provides counter pressure to the tubing in response to pressure caused by the rollers. As the rotor wheels turn, the rollers of the rotor wheels individually come into contact with the tubing and then disengage the tubing, causing the tubing to be pinched and then released to its natural state. Successive pinching and releasing of the tubing causes fluid to pass through the system and, thus, be dispensed or pumped.
Peristaltic pumps have been designed for applications where it is desirable to pump or dispense multiple fluids, however, there still exists a need for an addressable multi-channel pump. Currently, no one pump is capable of selecting one or more fluids for dispensing. For example, to achieve multiple fluid dispensing capability with existing technology, a separate pump is operated to pump each fluid, which typically requires a separate motor for each pump. Further, for example, in existing single-motor multi-channel peristaltic pumps, there is no selectivity and the fluids of all channels are dispensed at the same time.